JP4081433B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell having an electrolyte / electrode assembly formed by sandwiching an electrolyte between an anode side electrode and a cathode side electrode, and alternately laminating the electrolyte / electrode assembly and a separator.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. In this fuel cell, an electrolyte membrane / electrode structure comprising an anode catalyst and a cathode electrode each made of an electrode catalyst and porous carbon is provided on both sides of a solid polymer electrolyte membrane, and a separator (bipolar plate) is provided. ). Usually, a fuel cell stack in which a predetermined number of the fuel cells are stacked is used.

  In this type of fuel cell, a fuel gas (reactive gas) supplied to the anode electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is hydrogen ionized on the electrode catalyst, It moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas (reaction gas), for example, a gas mainly containing oxygen or air (hereinafter also referred to as oxygen-containing gas). Hydrogen ions, electrons and oxygen react to produce water.

  In the fuel cell described above, a fuel gas flow channel is provided in the surface of the anode-side separator so as to flow fuel gas so as to face the anode-side electrode, and in the surface of the cathode-side separator, facing the cathode-side electrode. An oxidant gas flow path for flowing an oxidant gas is provided. Further, a cooling medium flow path for flowing a cooling medium is provided along the surface direction of the separator between the anode side separator and the cathode side separator.

  This type of separator is usually made of a carbon-based material, but it has been pointed out that the carbon-based material cannot be thinned due to factors such as strength. Therefore, recently, a separator made of a thin metal plate (hereinafter also referred to as a metal separator), which is superior in strength to this type of carbon separator and can be easily thinned, is subjected to a pressing process on the metal separator to obtain a desired reaction gas. By shaping the flow path, a contrivance has been made to reduce the thickness of the metal separator to reduce the size and weight of the entire fuel cell.

  For example, a fuel cell 1 shown in FIG. 18 includes an electrolyte membrane / electrode structure 5 in which an electrolyte membrane 4 is interposed between an anode side electrode 2 and a cathode side electrode 3, and the electrolyte membrane / electrode structure 5. A pair of metal separators 6a and 6b is provided.

  The metal separator 6a is provided with a fuel gas flow path 7a for supplying fuel gas (for example, hydrogen-containing gas) on the surface facing the anode side electrode 2, while the metal separator 6b is provided with the cathode side electrode 3 An oxidant gas flow path 7b for supplying an oxidant gas (for example, an oxygen-containing gas such as air) is provided on the opposite surface. The metal separators 6a and 6b are provided with flat portions 8a and 8b that are in contact with the anode side electrode 2 and the cathode side electrode 3, and on the back surfaces (surfaces opposite to the contact surfaces) of the flat portions 8a and 8b. Cooling medium flow paths 9a and 9b for flowing the cooling medium are formed.

  However, in the metal separators 6a and 6b, when the flow path shapes of the fuel gas flow path 7a and the oxidant gas flow path 7b are set, the flow path shapes of the cooling medium flow paths 9a and 9b are inevitably determined. End up. In particular, in order to ensure a long gas flow path length, when the fuel gas flow path 7a and the oxidant gas flow path 7b are configured with serpentine flow paths meandering in the electrode plane, the cooling medium flow paths 9a, 9b The flow path shape is significantly limited, and the flow rate in the electrode surface varies.

  For this reason, a portion where the cooling medium stagnates occurs in the cooling medium flow paths 9a and 9b of the metal separators 6a and 6b, and the cooling medium may not be able to flow uniformly over the entire surface of the metal separators 6a and 6b. Accordingly, it has been pointed out that it is difficult to cool the electrode surface uniformly to obtain stable power generation performance.

  Therefore, for example, Patent Document 1 includes a metal separator, which has two metal plates that are formed with unevenness and form a gas flow path, and is sandwiched between the two metal plates to form an unevenness, and is cooled on both sides. A fuel cell separator having an intermediate metal plate forming a water flow path is disclosed.

Japanese Patent Laying-Open No. 2002-75395 (FIG. 3)

  However, in the above-mentioned Patent Document 1, the metal separator includes two metal plates that form a gas flow path and one intermediate metal plate that is sandwiched between the two metal plates and forms a cooling water flow path on the front and back sides. And a total of three metal plates are required. For this reason, particularly when a fuel cell stack is configured by laminating a large number of metal separators, the number of components is considerably increased and the manufacturing cost is increased, and the dimensions of the metal separators in the stacking direction are increased. There is a problem that the whole is enlarged.

  The present invention solves this type of problem, and provides a fuel cell capable of uniformly and reliably flowing a cooling medium in the plane of the separator with a simple configuration and ensuring good power generation performance. The purpose is to provide.

In the present invention, an electrolyte / electrode assembly is formed by sandwiching an electrolyte between an anode electrode and a cathode electrode, the electrolyte / electrode assembly and the separator are alternately stacked, and the center of both ends of the separator A reaction gas communication hole and a cooling medium communication hole are formed through the portion in the stacking direction.

  The separator includes at least a first metal plate and a second metal plate that are stacked on each other, and the first metal plate includes a flow path that supplies and bends the oxidant gas along the power generation surface of the cathode side electrode. While the flow path is provided, the second metal plate is provided with a fuel gas flow path including a flow path for supplying fuel gas and bending along the power generation surface of the anode side electrode.

Between the first and second metal plates, a cooling medium flow path for supplying a cooling medium along the surface direction of the separator, and the cooling medium flow path is branched in at least two opposite directions from the cooling medium communication hole. There are provided two or more buffer units communicating with each other. And at least 1 buffer part is provided with the convex part for restrict | limiting the flow of a cooling medium in the back side spaced apart from a cooling medium communicating hole, and distribute | circulating the said cooling medium uniformly in a cooling surface .

  Each of the first and second metal plates is provided with a bent channel, for example, an oxidant gas channel and a fuel gas channel including a serpentine channel, so that the first and second metal plates are formed between the first and second metal plates. The cooling medium flow path is partially different in the flow state of the cooling medium.

  Specifically, between the first metal plate and the second metal plate, there is an overlapping portion where the flow channel grooves overlap with each other and an intersection where the flow channel grooves intersect with each other. At that time, in the overlapping portion, the flow channel groove becomes a deep groove and the flow channel resistance is reduced, whereas in the intersection, the flow channel groove becomes a shallow groove and the flow channel resistance increases. For this reason, in the cooling medium flow path, the length of the overlapping portion on both ends is longer than that on the central portion, and the cooling medium flows easily on both ends.

  In view of this, a convex portion that restricts the flow of the cooling medium is provided corresponding to a portion where the cooling medium easily flows, that is, on the back side away from the cooling medium communication hole of the buffer portion.

  The reaction gas communication hole has a fuel gas inlet communication hole, an oxidant gas inlet communication hole, a fuel gas outlet communication hole, and an oxidant gas outlet communication hole, and the cooling medium communication hole includes a cooling medium inlet communication hole and a cooling medium. There are medium outlet communication holes, and the buffer part branches from the cooling medium inlet communication hole in at least two directions and communicates with the cooling medium flow path, and at least two from the cooling medium outlet communication hole. It is preferable to have two or more outlet buffer portions that branch in a direction and communicate with the cooling medium flow path.

  Further, the first metal plate is provided with a first inlet buffer portion and a first outlet buffer portion communicating with the cooling medium inlet communication hole and the cooling medium outlet communication hole, and the second metal plate has the cooling medium inlet port. It is preferable that a second inlet buffer portion and a second outlet buffer portion are provided at positions different from the first inlet buffer portion and the first outlet buffer portion, which communicate with the communication hole and the cooling medium outlet communication hole.

  Furthermore, the fuel gas inlet communication hole, the oxidant gas inlet communication hole, the cooling medium inlet communication hole, the fuel gas outlet communication hole, the oxidant gas outlet communication hole, and the cooling medium outlet communication hole are allotted to both ends of the separator. In addition, it is preferable that the cooling medium inlet communication hole and the cooling medium outlet communication hole are disposed at the center of both ends of the separator.

  According to the present invention, since the convex portion is provided in the buffer portion communicating with the cooling medium communication hole corresponding to the portion where the cooling medium easily flows, the flow of the cooling medium in the portion is restricted. For this reason, the flow state of the cooling medium is uniform over the entire cooling medium flow path. Thereby, with a simple configuration, the cooling medium can be uniformly and surely flowed in the plane of the separator, and the entire power generation surface can be effectively cooled to ensure good power generation performance.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to a first embodiment of the present invention, and FIG. 2 is a perspective explanatory view of a coolant flow path 42 (described later) constituting the fuel cell 10. FIG. 3 is an explanatory front view of the cooling medium flow path 42.

  The fuel cell 10 is configured by alternately laminating electrolyte membrane / electrode structures 12 and separators 13, and the separator 13 includes first and second metal plates 14 and 16 that are laminated to each other (see FIG. 1, see FIGS. 4 to 7).

  As shown in FIG. 1, an oxidant for supplying an oxidant gas, for example, an oxygen-containing gas, to one end edge of the fuel cell 10 in the direction of arrow B and communicating with each other in the direction of arrow A that is the stacking direction. A gas inlet communication hole 20a, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas outlet communication hole 24b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the arrow C direction (vertical direction). Arranged and provided.

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas inlet communication hole 24a for supplying fuel gas, and the cooling medium outlet communication hole for discharging the cooling medium. 22b and an oxidant gas outlet communication hole 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 26 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 28 and a cathode side electrode 30 that sandwich the solid polymer electrolyte membrane 26. With. The anode side electrode 28 and the cathode side electrode 30 are configured by notching the center of both ends in the direction of arrow B inward so as to avoid the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b.

  The anode side electrode 28 and the cathode side electrode 30 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. Respectively. The electrode catalyst layer is bonded to both surfaces of the solid polymer electrolyte membrane 26.

  As shown in FIGS. 1 and 8, an oxidant gas flow path 32 is provided on the surface 14a of the first metal plate 14 on the electrolyte membrane / electrode structure 12 side. The oxidant gas inlet communication hole 20a communicates with the oxidant gas outlet communication hole 20b. The oxidant gas flow path 32 communicates with an inlet buffer part 34a and an outlet buffer part 34b provided in the vicinity of the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b. The inlet buffer portion 34a and the outlet buffer portion 34b communicate with the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b through a plurality of connection paths 36a and 36b.

  The inlet buffer portion 34a and the outlet buffer portion 34b communicate with each other through a plurality of oxidant gas flow channel grooves 32a constituting the oxidant gas flow channel 32. The oxidant gas flow channel groove 32a extends in the direction of the arrow C while meandering in the direction of the arrow B. Specifically, the oxidant gas flow channel groove 32a constitutes a serpentine channel that is bent by one reciprocal half in the direction of the arrow B.

  A cooling medium flow path 42 is integrally formed on the surfaces 14b and 16a of the first metal plate 14 and the second metal plate 16 facing each other. 2 and 3, the cooling medium flow path 42 is provided in the vicinity of both ends of the cooling medium inlet communication hole 22a in the direction of the arrow C, for example, two inlet buffer portions 44 and 46, and a cooling medium outlet communication hole. For example, two outlet buffer portions 48 and 50 are provided near both ends in the direction of arrow C of 22b.

  The cooling medium inlet communication hole 22a and the inlet buffer portions 44 and 46 communicate with each other via a plurality of inlet flow channel grooves 52 and 54, respectively, while the cooling medium outlet communication hole 22b and the outlet buffer portions 48 and 50 respectively The plurality of outlet flow channel grooves 56 and 58 communicate with each other.

  The cooling medium flow path 42 has long straight flow path grooves 60, 62, 64 and 66 extending in the arrow B direction on the lower side, and a long straight line extending in the arrow B direction on the upper side. Shaped channel grooves 68, 70, 72 and 74. Between the linear flow channel grooves 66 and 68, linear flow channel grooves 76 and 78 are provided so as to extend a predetermined length in the arrow B direction.

  The linear flow channel grooves 60 to 74 communicate with each other via linear flow channel grooves 80 and 82 extending in the direction of arrow C. The straight flow channel grooves 62 to 72, 76, and 78 communicate with each other through the straight flow channel grooves 84 and 86 extending in the direction of the arrow C, and the straight flow channel grooves 64, 66, and 76 are connected to the straight flow channels. The channel grooves 68, 70, and 78 communicate with each other through linear channel grooves 88 and 90 that intermittently extend in the direction of arrow C.

  The cooling medium flow path 42 is distributed between the first metal plate 14 and the second metal plate 16, and the cooling medium flow path 42 is formed by overlapping the first and second metal plates 14, 16 with each other. It is formed.

  As shown in FIG. 9, a part of the cooling medium flow path 42 is formed on the surface 14 b of the first metal plate 14. In addition, although the oxidant gas flow path 32 formed on the surface 14a protrudes in a convex shape on the surface 14b, the convex portion is not shown for easy understanding of the cooling medium flow channel 42. . Similarly, in the surface 16a of the second metal plate 16 shown in FIG. 10, the portion where the fuel gas flow path 98 formed on the surface 16b protrudes in a convex shape on the surface 16a is not shown.

  The surface 14b is provided with an inlet buffer portion 44 that communicates with the cooling medium inlet communication hole 22a and an outlet buffer portion 50 that communicates with the cooling medium outlet communication hole 22b. On the surface 14b, groove portions 60a to 78a constituting a part of the linear flow channel grooves 60 to 78 are provided over a predetermined length in the direction of the arrow B, and also constitute the linear flow channel grooves 80 to 90. Groove portions 80a to 90a are provided over a predetermined length in the direction of arrow C, respectively.

  The inlet buffer portion 44 is provided with a convex portion 92a that restricts the flow of the cooling medium on the far side away from the cooling medium inlet communication hole 22a, that is, on the lower end side of the cooling medium flow path 42 (FIGS. 6 and 6). 9). The outlet buffer 50 is provided with a convex portion 92b that regulates the flow of the cooling medium on the back side away from the cooling medium outlet communication hole 22b, that is, on the upper end side of the cooling medium flow path 42. The convex portions 92a and 92b are integrally formed with the first metal plate 14 by press molding. The convex portions 92a and 92b form a concave portion on the surface 14a side, and the concave portion has a blocking structure so that an oxidant gas does not flow in.

  A first seal member 94 is integrally provided on the surfaces 14a and 14b of the first metal plate 14 by injection molding or the like around the outer peripheral edge of the first metal plate 14. The first seal member 94 constitutes a flat seal, and the surface 14a covers the oxidant gas inlet communication hole 20a, the oxidant gas outlet communication hole 20b, and the oxidant gas flow path 32 as shown in FIG. And a linear seal 94a for preventing leakage of the oxidant gas. A part of the linear seal 94a constitutes a partition wall that forms the connecting paths 36a and 36b.

  As shown in FIG. 10, an inlet buffer portion 46 and an outlet buffer portion 48 are provided on the surface 16 a of the second metal plate 16. On the surface 16a, groove portions 60b to 78b constituting a part of the linear flow channel grooves 60 to 78 are provided over a predetermined length in the arrow B direction, and also constitute the linear flow channel grooves 80 to 90. The groove portions 80b to 90b are provided in a direction indicated by an arrow C over a predetermined length.

  In the cooling medium flow path 42, a part of the straight flow path grooves 60 to 78 extending in the direction of the arrow B makes the respective groove portions 60a to 78a and 60b to 78b face each other, thereby changing the flow path cross-sectional area. The main flow path is configured to be twice as large as that of (see FIGS. 2 and 3). The straight channel grooves 80 to 90 are partly polymerized and distributed to the first and second metal plates 14 and 16, respectively.

  As shown in FIG. 10, the inlet buffer portion 46 has a convex portion 96 a that regulates the flow of the cooling medium on the far side away from the cooling medium inlet communication hole 22 a, that is, on the upper end side of the cooling medium flow path 42. Provided. The outlet buffer 48 is provided with a convex portion 96b that regulates the flow of the cooling medium on the back side away from the cooling medium outlet communication hole 22b, that is, on the lower end side of the cooling medium flow path 42. As shown in FIG. 11, the convex portions 96a and 96b form a concave portion on the surface 16b side, and this concave portion has a closed structure so that fuel gas does not flow in.

  A fuel gas flow path 98 is provided on the surface 16b of the second metal plate 16 facing the electrolyte membrane / electrode structure 12 side. The fuel gas channel 98 communicates with an inlet buffer portion 100a provided in the vicinity of the fuel gas inlet communication hole 24a and an outlet buffer portion 100b provided in the vicinity of the fuel gas outlet communication hole 24b.

  The inlet buffer unit 100a and the outlet buffer unit 100b communicate with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b through a plurality of connection paths 102a and 102b. The plurality of fuel gas flow channel grooves 98a constituting the fuel gas flow channel 98 extend in the direction of the arrow C while meandering in the direction of the arrow B. Specifically, the fuel gas flow channel grooves 98a are bent by one reciprocal half in the direction of the arrow B. Serpentine flow path is configured.

A second seal member 104 is integrally provided on the surfaces 16a and 16b of the second metal plate 16 by injection molding or the like around the outer peripheral edge of the second metal plate 16. The second seal member 104 constitutes a flat seal, and the surface 16a covers the cooling medium inlet communication hole 22a, the cooling medium outlet communication hole 22b, and the cooling medium flow path 42 as shown in FIG. A linear seal 104a is provided to prevent leakage. As shown in FIG. 11, the surface 16 b has a linear seal 104 b that covers the fuel gas inlet communication hole 24 a, the fuel gas outlet communication hole 24 b, and the fuel gas flow path 98 to prevent leakage of fuel gas.

  A part of the linear seal 104a constitutes a partition wall that forms the inlet channel grooves 52 and 54 and the outlet channel grooves 56 and 58 (see FIG. 10). Part of the linear seal 104b constitutes a partition wall that forms the connecting paths 102a and 102b (see FIG. 11).

  The operation of the fuel cell 10 according to the first embodiment configured as described above will be described below.

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  The oxidant gas is introduced into the oxidant gas channel 32 of the first metal plate 14 from the oxidant gas inlet communication hole 20a. In the oxidant gas flow path 32, as shown in FIG. 8, the oxidant gas is once introduced into the inlet buffer 34a and then dispersed in the plurality of oxidant gas flow path grooves 32a. Therefore, the oxidant gas moves along the cathode side electrode 30 of the electrolyte membrane / electrode structure 12 while meandering through the respective oxidant gas flow channel grooves 32a.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 98 of the second metal plate 16 from the fuel gas inlet communication hole 24a. In the fuel gas flow path 98, as shown in FIG. 11, the fuel gas is once introduced into the inlet buffer portion 100a and then dispersed into the plurality of fuel gas flow path grooves 98a. Further, the fuel gas meanders through each fuel gas channel groove 98 a and moves along the anode side electrode 28 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 30 and the fuel gas supplied to the anode side electrode 28 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 30 is discharged from the outlet buffer part 34b to the oxidant gas outlet communication hole 20b (see FIG. 8). Similarly, the fuel gas consumed by being supplied to the anode electrode 28 is discharged from the outlet buffer unit 100b to the fuel gas outlet communication hole 24b (see FIG. 11).

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 22 a is introduced into a cooling medium flow path 42 formed between the first and second metal plates 14 and 16. In this cooling medium flow path 42, as shown in FIGS. 2 to 5, the cooling medium flow path 42 is connected to the inlet buffer via the inlet flow path grooves 52 and 54 extending in the direction of arrow C from the cooling medium inlet communication hole 22a. Once introduced into the sections 44 and 46.

  As shown in FIGS. 2 and 3, the cooling medium introduced into the inlet buffers 44 and 46 is dispersed in the linear flow channel grooves 60 to 78 and moves in the horizontal direction (arrow B direction). The portion is supplied to the linear flow channel grooves 80 to 90. Therefore, after the cooling medium is supplied over the entire power generation surface of the electrolyte membrane / electrode structure 12, the cooling medium is once introduced into the outlet buffer portions 48 and 50, and further through the outlet passage grooves 56 and 58. It is discharged to 22b.

  In this case, in the first embodiment, as shown in FIGS. 2 and 3, in the linear flow channel grooves 60 to 78 constituting the cooling medium flow channel 42, the flow channel cross-sectional area is enlarged in the arrow B direction. The extending main flow path portion is configured to be elongated toward the outside in the vertical direction (arrow C direction). Specifically, in the straight channel grooves 60 to 78, the main channel length in the direction of arrow B is the shortest in the straight channel grooves 66 and 68, while the longest in the straight channel grooves 60 and 74, respectively. The main flow path length difference is considerably large. The cooling medium passes through the intersection where the flow resistance is large from the inlet buffer 44 toward the straight flow grooves 66 and 68, and also passes through the intersection in the outlet buffer 48 from the straight flow grooves 66 and 68. Therefore, the flow rate decreases in the linear flow channel grooves 66 and 68. Therefore, the flow rate of the cooling medium flowing in the direction of the arrow B along the straight flow path grooves 60 to 78 is likely to vary, and in particular, the flow rates in the straight flow path grooves 60 and 74 on both the upper and lower ends are considerably increased. End up.

  Therefore, in the first embodiment, convex portions 92a and 96b for restricting the flow of the cooling medium are provided on the lower end side of the inlet buffer portion 44 and the outlet buffer portion 48, and the inlet buffer portion 46 and the outlet buffer portion 50 are provided. Similarly, convex portions 96a and 92b for restricting the flow of the cooling medium are provided on the upper end side of.

  In the inlet buffer unit 44, as shown in FIG. 6, the convex portion 92a provided on the surface 14b of the first metal plate 14 is in contact with the surface 16a of the second metal plate 16, and the flow of the cooling medium is restricted. The In the inlet buffer unit 46, as shown in FIG. 7, the convex portion 96a provided on the second metal plate 16 contacts the surface 14b of the first metal plate 14 to regulate the flow of the cooling medium.

  Similarly, in the outlet buffer portions 48 and 50, the convex portion 96b of the second metal plate 16 contacts the surface 14b of the first metal plate 14, while the convex portion 92b of the first metal plate 14 The two metal plates 16 are in contact with the surface 16a to restrict the flow of the cooling medium.

  This restricts the flow of the cooling medium at both ends (upper and lower ends) in the direction of arrow C of the cooling medium flow path 42, so that the cooling medium is uniform in the direction of arrow B throughout the straight flow path grooves 60 to 78. A smooth flow state can be obtained. Specifically, the flow rate of the cooling medium flowing through the cooling medium flow path 42 was detected in a configuration in which the convex portions 92a, 96a and 96b, 92b were not provided in the inlet buffer portions 44, 46 and the outlet buffer portions 48, 50. As a result, as shown in FIG. 12, the flow rate of the cooling medium increased considerably at the upper and lower ends of the cooling medium flow path 42. Further, the flow rate decreased in the straight flow path grooves 66 and 68.

  On the other hand, in the first embodiment, as shown in FIG. 13, the cooling medium flow path 42 is provided with convex portions 92a, 96a, 96b, and 92b corresponding to the upper and lower end portions thereof, thereby the cooling medium. The flow rate of the cooling medium along the direction of arrow C in the flow path 42 was maintained substantially uniform. Therefore, in the first embodiment, it is possible to supply the cooling medium uniformly and reliably in the plane of the separator 13 with a simple configuration, and it is possible to obtain an effect that it is possible to ensure good power generation performance. .

  FIG. 14 is a cross-sectional explanatory view of the convex portion 92c constituting the fuel cell 10a according to the second embodiment of the present invention, and FIG. 15 is a cross-sectional explanatory view of the convex portion 96c constituting the fuel cell 10a. . The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third embodiment described below, detailed description thereof is omitted.

  In the convex portion 92 c, the convex portion 110 is provided on the surface 14 b of the first metal plate 14. The convex portion 110 is integrally formed on the surface 14b of the first metal plate 14 with a rubber material, and the convex portion 110 abuts on the surface 16a of the second metal plate 16 to restrict the flow of the cooling medium. . As shown in FIG. 15, in the convex portion 96 c, similarly, a rubber material is integrally formed on the surface 16 a of the second metal plate 16 to provide the convex portion 112. The protrusion 112 abuts on the surface 14b of the first metal plate 14 and restricts the flow of the cooling medium.

  In the second embodiment configured as described above, the convex portions 110 and 112 are provided by integrally molding a rubber material on the second and first metal plates 16 and 14, respectively, and the convex portions 92a and 96a are provided. The same effects as those of the first embodiment in which the second and first metal plates 16 and 14 are press-formed can be obtained.

  FIG. 16 is a cross-sectional explanatory view of the convex portion 92d constituting the fuel cell 10b according to the third embodiment of the present invention, and FIG. 17 is a cross-sectional explanatory view of the convex portion 96d constituting the fuel cell 10b. .

  In the convex portion 92d, a rubber convex portion 114 molded in advance into a predetermined shape is attached to the surface 14b of the first metal plate 14, and the convex portion 114 contacts the surface 16a of the second metal plate 16. Touch. As shown in FIG. 17, in the convex portion 96d, a rubber convex portion 116, which is similarly molded in a predetermined shape, is attached to the surface 16a of the second metal plate 16, and the convex portion 116 is 1 is in contact with the surface 14 b of the metal plate 14. Thereby, in 3rd Embodiment, the effect similar to 1st and 2nd embodiment is acquired.

It is a principal part disassembled perspective view of the fuel cell which concerns on the 1st Embodiment of this invention. It is a perspective explanatory view of the cooling medium flow path which constitutes the fuel cell. It is front explanatory drawing of the said cooling medium flow path. FIG. 4 is a sectional view of the fuel cell taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the fuel cell taken along line VV in FIG. 3. FIG. 6 is a cross-sectional view of the fuel cell taken along line VI-VI in FIG. 3. It is the VII-VII sectional view taken on the line of the said fuel cell in FIG. It is explanatory drawing of one surface of the 1st metal plate which comprises the said fuel cell. It is explanatory drawing of the other surface of the said 1st metal plate. It is explanatory drawing of one surface of the 2nd metal plate which comprises the said fuel cell. It is explanatory drawing of the other surface of the said 2nd metal plate. It is explanatory drawing of the flow volume of the cooling medium at the time of using the comparative example which does not provide a convex part. It is explanatory drawing of the flow volume of the cooling medium of 1st Embodiment. It is a section explanatory view of one convex part which constitutes a fuel cell concerning a 2nd embodiment of the present invention. It is a cross-sectional explanatory drawing of the other convex part which comprises the said fuel cell. It is a section explanatory view of one convex part which constitutes a fuel cell concerning a 3rd embodiment of the present invention. It is a cross-sectional explanatory drawing of the other convex part which comprises the said fuel cell. FIG. 3 is a cross-sectional explanatory view of a fuel cell in which an electrolyte membrane / electrode structure is sandwiched between a pair of metal separators.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a, 10b ... Fuel cell 12 ... Electrolyte membrane electrode assembly 13 ... Separator 14, 16 ... Metal plate 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 26 ... Solid polymer electrolyte membrane 28 ... Anode side electrode 30 ... Cathode side electrode 32 ... Oxidant gas channel 32a ... Oxidant gas channel Groove 34a, 44, 46, 100a ... Inlet buffer part 34b, 48, 50, 100b ... Outlet buffer part 42 ... Cooling medium channel 52, 54 ... Inlet channel groove 56, 58 ... Outlet channel groove 60-90 ... Straight line -Like channel grooves 92a to 92d, 96a to 96d, 110 to 116 ... convex portion 98 ... fuel gas channel

Claims (4)

The electrolyte / electrode assembly includes an electrolyte sandwiched between an anode side electrode and a cathode side electrode, and the electrolyte / electrode assembly and separator are alternately stacked, and the stacking direction is provided at the center of both ends of the separator. A reaction gas communication hole and a cooling medium communication hole are formed through the fuel cell,
The separator includes at least first and second metal plates stacked on each other,
The first metal plate is provided with an oxidant gas flow path including a flow path for supplying and bending an oxidant gas along the power generation surface of the cathode side electrode, while the second metal plate is provided with the anode side electrode. Providing a fuel gas flow path including a flow path for supplying and bending fuel gas along the power generation surface of
Between the first and second metal plates, a cooling medium flow path for supplying a cooling medium along the surface direction of the separator;
Two or more buffer portions that branch from the cooling medium communication hole in at least two opposite directions and communicate with the cooling medium flow path;
And at least one of the buffer portions is provided with a convex portion for restricting the flow of the cooling medium on the back side away from the cooling medium communication hole to distribute the cooling medium uniformly in the cooling surface. A fuel cell characterized by the above. 2. The fuel cell according to claim 1, wherein the reaction gas communication hole has a fuel gas inlet communication hole, an oxidant gas inlet communication hole, a fuel gas outlet communication hole, and an oxidant gas outlet communication hole.
The cooling medium communication hole has a cooling medium inlet communication hole and a cooling medium outlet communication hole,
The buffer section is branched in at least two directions from the cooling medium inlet communication hole and communicates with the cooling medium flow path, and two or more inlet buffer sections;
Two or more outlet buffer portions branched in at least two directions from the cooling medium outlet communication hole and communicating with the cooling medium flow path;
A fuel cell comprising: 3. The fuel cell according to claim 2, wherein the first metal plate is provided with a first inlet buffer portion and a first outlet buffer portion communicating with the cooling medium inlet communication hole and the cooling medium outlet communication hole,
The second metal plate communicates with the cooling medium inlet communication hole and the cooling medium outlet communication hole, and has a second inlet buffer portion and a second outlet at a position different from the first inlet buffer portion and the first outlet buffer portion. 2. A fuel cell comprising a two-outlet buffer unit. 4. The fuel cell according to claim 2, wherein the fuel gas inlet communication hole, the oxidant gas inlet communication hole, the cooling medium inlet communication hole, the fuel gas outlet communication hole, the oxidant gas outlet communication hole, and the cooling. The medium outlet communication holes are distributed to both ends of the separator three by three,
The fuel cell according to claim 1, wherein the cooling medium inlet communication hole and the cooling medium outlet communication hole are disposed at the center of both ends of the separator.

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